Preventing Aim At An Undesired Target

Abstract

Electronic system controls changes in orientation of optical instrument. Slew-control system includes avoidance-control logic, which overrides slew-control error generator when line of sight of instrument comes within cone of avoidance around line of sight to Sun. Normal slewing trajectory interrupted by avoidance-control logic, which computes actuator torques taking line of sight around cone of avoidance. Used to protect delicate photodetectors in servocontrolled infrared spectrometer or imaging instrument against damage occurring if instrument aimed at Sun or another excessively bright object.